Borescope shows corrosion

[rotorman]

I received my oil sample results and after 120 hrs on the rebuilt IO360 A3D. This is the 6th report flagging Chrome staying high at 10 vs normal 2 and nickel at 5 vs normal 1.  The report states possible excessive wear on chrome plated piston rings and nickel exhaust valve guides. Neither of these are on an upward trend and oil usage is very low. The filter associated with this oil sample had no metal.  Any opinions on on whether this is cause for alarm?

Sorry for the repeat post. This post needed a new title.

Edited July 11, 2023 by rotorman

[PT20J]

You said “rebuilt” so I assume it’s a Lycoming factory rebuilt engine since only Lycoming can rebuild - everyone else overhauls. I’d discuss it with Lycoming.

[A64Pilot]

I wouldn’t do anything unless some kind of symptoms appear. 

I’m assuming an overhaul, but whoever did whatever I’d contact them by some kind of traceable contact informing them and asking their opinion. I’m thinking Email.

Not sure what good being able to prove you brought it to their attention could do, but I would want to be able to.

[rotorman]

4 hours ago, PT20J said:

You said “rebuilt” so I assume it’s a Lycoming factory rebuilt engine since only Lycoming can rebuild - everyone else overhauls. I’d discuss it with Lycoming.

Sorry for the bad info. Overhauled by Western Skyways,

[PT20J]

39 minutes ago, rotorman said:

Sorry for the bad info. Overhauled by Western Skyways,

They’re good - I’d discuss it with them. 

[rotorman]

16 minutes ago, PT20J said:

They’re good - I’d discuss it with them. 

Talked to Larry Flattery at Western Skyways. He recommended borescope. Then run it hard prior to next sample in 20 hrs. I have scheduled a borescope for next week. I've been loll gaging around my home field at slow speeds in order to stay current and keep the airplane flying. Normally at around 20 map and 22 rpm. He said that could have an effect.  

[EricJ]

26 minutes ago, rotorman said:

Talked to Larry Flattery at Western Skyways. He recommended borescope. Then run it hard prior to next sample in 20 hrs. I have scheduled a borescope for next week. I've been loll gaging around my home field at slow speeds in order to stay current and keep the airplane flying. Normally at around 20 map and 22 rpm. He said that could have an effect.  

A very common approach is to run full throttle and 2500 rpm.   It is not an uncommon practice to go full throttle (aka WOT) on takeoff and leave it there until descent to landing, with propeller full forward from takeoff until top of climb, then back to 2500.   I've run mine this way since I bought it.    

[Utah20Gflyer]

My chromium has been 7 ppm for every oil sample so far with no comment from Blackstone,  I do however have chrome cylinders.  You didn’t verify whether you have chrome cylinders but I assume you don’t based on the comments from Blackstone?  
 

If I were in your shoes I’d just keep flying until something actually happens.  Although borescoping isn’t a bad idea.  10 ppm is not a lot of material and not hitting an average number exactly doesn’t necessarily mean anything.  So as long as the borescoping doesn’t reveal anything I would think you’ll be good.  

Edited July 6, 2023 by Utah20Gflyer

[Pinecone]

You have to run high cylinder pressures to seat the rings.  65 - 75% power until they seat.  And I would run closer to 75%.  Both Lycoming and Continental break in instructions say this.

If you run low power settings, you run the risk of glazing the cylinders.  If this happens, you have to remove all of them and rehone them.  We had to do this with a CAP 182.

[rotorman]

4 hours ago, Pinecone said:

You have to run high cylinder pressures to seat the rings.  65 - 75% power until they seat.  And I would run closer to 75%.  Both Lycoming and Continental break in instructions say this.

If you run low power settings, you run the risk of glazing the cylinders.  If this happens, you have to remove all of them and rehone them.  We had to do this with a CAP 182.

I ran at full power during the break in. The cylinder head temps drop down nicely and the oil consumption came down to a qt at 9 hrs. There is no metal in the filter. I'm using X/C 20-50.  I've only been running the lower power settings for the last 10 hrs or so. My normal mission from Bend to Seattle, about 1.5 hrs, went away at the end of March. Since then I fly once a week for an hour locally at 20 map 22 rpm. 

[Pinecone]

Good

 

[A64Pilot]

3 hours ago, rotorman said:

I ran at full power during the break in. The cylinder head temps drop down nicely and the oil consumption came down to a qt at 9 hrs. There is no metal in the filter. I'm using X/C 20-50.  I've only been running the lower power settings for the last 10 hrs or so. My normal mission from Bend to Seattle, about 1.5 hrs, went away at the end of March. Since then I fly once a week for an hour locally at 20 map 22 rpm. 

You should be fine then, once an engine has been properly broken in low power as long as you can get the temps into the green should be fine.

In fact in several publications Lycoming says for maximum life run the engine at 65% or lower power.

My personal belief is low power AND LOP, but if LOP your % power can be much lower than you might think. 

For instance I run 23 squared down low and 8GPH, the 8 GPH means I’m making 120 HP and 120 is 60% power. Intuitively you would think 23 squared would be much higher and ROP it is.

[Pinecone]

I did a trip about a month ago.  I was headed to an airport that was going to have a TFR go active for a practice day for an airshow.  GPS showed me arriving about 10 minutes AFTER the TFR went into affect.  Just going from LOP to ROP, without any other changes, I arrived 15 minutes before the TFR.  But at a higher cost for fuel.

[rotorman]

The borescope shows corrosion in all 4 cylinders. The IA speculates that the only way he sees that this is possible with only 120 hrs on the rebuild is the cylinder were on a humid shelf prior to installation and were not properly inspected. He says the corrosion is below the are of the cylinder that would effect compression. The rebuild was done just short of 3 years ago and the airplane has never sat for more than 2 weeks.  These are shots of 3 out of the 4 cylinders  What is my best course of action from here?

 r

 

Edited July 11, 2023 by rotorman

[Rwsavory]

I wouldn’t do anything but keep running it unless you have some actual symptoms affecting performance. 

[A64Pilot]

Honestly, your only course of action if you want them “right” is to replace them.

I wouldn’t though, I’d keep flying but start saving because it’s coming. It’s not if, but when. 

However it’s my understanding that for some reason angle valve cylinders are as rare as hens teeth. If true I can’t explain why.

I believe there are no PMA angle valve cylinders? Could be wrong though.

[rotorman]

1 hour ago, A64Pilot said:

Honestly, your only course of action if you want them “right” is to replace them.

I wouldn’t though, I’d keep flying but start saving because it’s coming. It’s not if, but when. 

However it’s my understanding that for some reason angle valve cylinders are as rare as hens teeth. If true I can’t explain why.

I believe there are no PMA angle valve cylinders? Could be wrong though.

So I'm talking to Western Sky Airways about this problem. I've sent them the borescope photos and the oil analysis. I will report their verdict.

I don't know enough about this to understand what your point is about angle valve cylinders. Plz elaborate.

[A64Pilot]

There are a couple of different versions of Lycoming 360’s if we ignore narrow vs wide deck.

The parallel valve are all I believe 180 HP motors, the 200 HP are angle valve, think Hemi, as you have a J model I’m pretty sure you have an angle valve motor as I do.

There are PMA parallel valve cylinders out there like Milleniums etc. but I think Lycoming is the only source of angle valve cylinders, and I think they are back ordered for a year I have heard. If that’s true then only ones available are overhauled ones, or have yours overhauled and my guess is yours may not be able to be overhauled, but that’s just a guess as I’m not familiar what the requirement for re-chroming is, or if it’s even do-able.

I have never tried ordering angle valve cylinders, so I may be wrong.

Edited July 13, 2023 by A64Pilot

[MB65E]

Keep flying. The Cylinders will last a long time in that condition. 
-Matt

[N201MKTurbo]

Continental makes PMA angle valve cylinders.

[A64Pilot]

3 hours ago, N201MKTurbo said:

Continental makes PMA angle valve cylinders.

I had forgotten that, but Conti just doesn’t seem to have a great rep with Cylinders, so I guess I hadn’t considered them.

I wonder if Lycoming will answer with PMA Continental 550 cylinders?

According to the people I worked with in GE the money is in parts, they pretty much give the new motors (big jets) away knowing that they will make their money on parts.

In that business a competitor PMA’ing your parts is very disturbing. I wonder if Conti trying to get in on Lycoming parts is as big a shake up as it was for GE?

Continental is Chinese owned, so I’d suspect that Gentleman’s agreements of times past likely don’t mean anything.

I think if Lycoming built Conti cylinders that were quality build they would own the replacement cylinder market?

But, why can’t Lycoming build their own cylinders? Angle valve cylinders go for almost twice what Parallel ones do, surely there is profit there?

Edited July 13, 2023 by A64Pilot

[N201MKTurbo]

8 minutes ago, A64Pilot said:

I had forgotten that, but Conti just doesn’t seem to have a great rep with Cylinders.

I wonder if Lycoming will answer with PMA Continental 550 cylinders?

According to the people I worked with in GE the money is in parts, they pretty much give the new motors away knowing that they will make their money on parts.

‘In that business a competitor PMA’ing your parts is very disturbing. I wonder if Conti trying to get in on Lycoming parts is as big a shake up as it was for GE?

Continental is Chinese owned, so I’d suspect that Gentleman’s agreements of times past likely don’t mean anything.

Continental bought ECI who made Lycoming cylinders. 
 

https://www.avweb.com/ownership/continental-buys-eci/

[A64Pilot]

1 minute ago, N201MKTurbo said:

Continental bought ECI who made Lycoming cylinders. 

If they were trying to get out of their OEM cylinder problems, they didn’t buy much did they? Of course with the AD’s I guess ECI didn’t cost much?

[Pinecone]

It seems like the best move would be to order cylinders, but keep flying.  With some luck, you won't need the cylinders until after they are delivered.

AFAIK you cannot rebuild chromed cylinders.

[PT20J]

Lycoming brought cylinder head machining in house just before Covid and was working through start up issues when the factory shut down for Covid. Then, during Covid owners decided it was a good time to overhaul and homebuilders decided it was a good time to order engines (Lycoming told me that Van’s is by far their largest customer now). Orders spiked and production was halted. They are still trying to catch up although they have 6 automated head machining lines running 24/7. Lead time was a year when I visited the factory last fall. Not sure what it is now. 

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